This disclosure relates generally to analytical instrumentation systems, and more particularly, to systems and methods for quantifying compounds in fluids, such as gases, vapors, and liquids, and solids.
Sensor methods and devices for quantifying volatile and nonvolatile compounds in fluids are known in the art. Typically, quantification of these parameters is performed using dedicated sensor systems that are specifically designed for this purpose. These sensor systems operate using a variety of principles including electrochemical, optical, acoustic and magnetic. Alternatively, a variety of colorimetric liquid and solid reagents are available to perform visual evaluation of color change.
In the art, CD/DVD drives were suggested for conducting optical inspection of biological, chemical, and biochemical samples. However, to make them useful for detection of parameters not related to digital data stored on optical media, the optical system of the drives must be modified. An optical disc drive described in U.S. Pat. No. 5,892,577 is modified to obtain the information related to chemical and biochemical detection. This modification included an addition of one or two optical detectors that are used for transmission measurements. An original optical detector of the drive is used to read digital addresses on the disc associated with an analyte-sensitive spot. Added detectors operating in transmission mode provide information on the sample to be inspected. This information from the additional detectors can be quantitative with 256 grey levels.
For operation of such a modified optical disc drive, special optical discs are prepared. Such discs have a semi-reflective layer to reflect a portion of light to one detector and transmit a portion of light to another detector, as disclosed in U.S. Pat. No. 6,327,031.
U.S. Pat. No. 6,342,349 describes another optical-drive-based measurement system. In this system, analyte-specific signal elements are disposed with the optical disc's tracking features. Thus, the analyte-specific signal elements are readable by the optics used for tracking, although modified or additional optics elements are added. For the system to be applicable, a signal responsive moiety is of a small size, compatible with the size of the focused light beam of the optical drive and is reflective. Most preferably, the signal response moiety is a gold microsphere with a diameter between 1 and 3 micrometers. The assay type used in this optical detection system is of a binary nature (see U.S. Pat. No. 6,342,349, col. 15, lines 23-37) and is not easily emendable to quantitative analysis based on light absorbance, reflection, scatter, or other optical phenomena.
Another method has also been described to screen the recognition between small molecule ligands and biomolecules using a conventional CD player. A procedure was developed to attach ligands to the reading face of a CD by activating the terminus of polycarbonate, a common polymer composite within the reading face of the CD. Displays were generated on the surface of a CD by printing tracks of ligands on the disc with an inkjet printer. Using this method, discs were created with entire assemblies of ligand molecules distributed into separate blocks. A molecular array was developed by assembling collections of these blocks to correlate with the CDROM-XA formatted data stored within the digital layer of the disc. Regions of the disc containing a given ligand or set of ligands were marked by its spatial position using the tracking and header information. Recognition between surface expressed ligands and biomolecules was screened by an error determination routine (see Org. Biomol. Chem., 1, 3244-3249 (2003)).
Different types of analyte-specific signal elements are also known in the art. International patent application WO 99/35499 describes the use of colloidal particles, microbeads, and the regions generated by a corrosive attack on one or several layers of a compact disc as a result of binding between the target molecule and its non-cleavable capture molecule. The analyte-specific signal elements can be arranged in arrays, for example, combinatorial arrays (International patent application WO 98/12559). In addition to solid and gel types of analyte-specific signal elements, other types include liquid-containing regions (Gamera Bioscience System, see: Anal. Chem. 71 4669-4678 (1999)).
In a related art, remote automated sensors have been employed for a variety of applications ranging from the cost-effective monitoring of industrial processes, to the determination of chemicals toxic to humans at locations of interest, to analysis of processes in difficult-to-access locations. For these and many other reasons, a wide variety of sensors have been reported that operate in the automatic, unattended mode. For example, sensors were reported that operate remotely for detection of toxic vapors, uranium ions, and many other species. Measurements have also been done remotely in space on manned and unmanned spacecraft.
Remote measurement systems can be initiated and monitored via the Internet where a dedicated sensor is connected to a computer that receives commands via the Internet as described in U.S. Pat. Nos. 5,931,913, 6,002,996, 6,182,497, 6,311,214, 6,332,193, 6,360,179, 6,405,135, and 6,422,061. Generally, upon receiving a command, the computer initiates a sensor that is specifically designed to perform a sensing function and is connected to the computer. The sensor performs the measurement, the computer receives the sensor signal, and optionally, sends the signal back to a control station.
Automated computer-controlled sensors for remote unattended operation known in the art have two distinct components. These components are (1) a sensor itself and (2) a computer. These components are designed and built to perform initially separate functions and further are combined into a remotely operated sensor system. The limitations of such approach include development of a sensor itself, and its adaptation for computer control.